Direct Numerical Simulation of Sprays: Turbulent Dispersion, Evaporation and Combustion
نویسنده
چکیده
Numerical procedures to describe the dispersion, evaporation and combustion of a polydisperse liquid fuel in a turbulent oxidizer are presented. Direct Numerical Simulation (DNS) allows one to describe accurately the evolution of the fully compressible gas-phase coupled with a Lagrangian description in order to describe two-phase flows. Standard coupling is used for the Eulerian/Lagrangian system while some practical issues related to the reactive source terms are addressed by suggesting a fast single-step Arrhenius law allowing one to capture the main fundamental properties of the flame whatever the local equivalence ratio. Then some basic procedures to describe spray preferential segregation in a turbulent reactor are described. Eventually spray combustion is addressed by first demonstrating the complex interactions caused by the presence of an evaporating liquid phase: definition of various equivalence ratios, apparition of flame instabilities for a unit Lewis number, etc. Then a history of the development of the existing spray combustion diagrams is presented to display the possible flame structures and combustion regimes encountered in spray combustion.
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